fix(chat): image send 500 + table/newline formatting (v2026.07.20.1708)

backend/python/app/api/chat_media.py

@@ -1430,7 +1430,7 @@ async def _generate_media_task(ai_msg_id: str, ai_model_id: str, prompt: str, us
         logger.info(f"[_generate_media_task] 启动 media 生成 msg={ai_msg_id} model={ai_model_id} prompt={prompt[:60]!r}")
         caps = [c.lower() for c in (ai_model.capabilities or [])]
         is_video = "video" in caps
-        timeout_seconds = 300 if is_video else 90
+        timeout_seconds = 300 if is_video else 180
         try:
             result = await asyncio.wait_for(
                 _generate_media(db, ai_model, prompt, user_id),